Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * 2002-10-18 written by Jim Houston jim.houston@ccur.com |
| 3 | * Copyright (C) 2002 by Concurrent Computer Corporation |
| 4 | * Distributed under the GNU GPL license version 2. |
| 5 | * |
| 6 | * Modified by George Anzinger to reuse immediately and to use |
| 7 | * find bit instructions. Also removed _irq on spinlocks. |
| 8 | * |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 9 | * Modified by Nadia Derbey to make it RCU safe. |
| 10 | * |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 11 | * Small id to pointer translation service. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | * |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 13 | * It uses a radix tree like structure as a sparse array indexed |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | * by the id to obtain the pointer. The bitmap makes allocating |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 15 | * a new id quick. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | * |
| 17 | * You call it to allocate an id (an int) an associate with that id a |
| 18 | * pointer or what ever, we treat it as a (void *). You can pass this |
| 19 | * id to a user for him to pass back at a later time. You then pass |
| 20 | * that id to this code and it returns your pointer. |
| 21 | |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 22 | * You can release ids at any time. When all ids are released, most of |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 23 | * the memory is returned (we keep MAX_IDR_FREE) in a local pool so we |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 24 | * don't need to go to the memory "store" during an id allocate, just |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | * so you don't need to be too concerned about locking and conflicts |
| 26 | * with the slab allocator. |
| 27 | */ |
| 28 | |
| 29 | #ifndef TEST // to test in user space... |
| 30 | #include <linux/slab.h> |
| 31 | #include <linux/init.h> |
Paul Gortmaker | 8bc3bcc | 2011-11-16 21:29:17 -0500 | [diff] [blame] | 32 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | #endif |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 34 | #include <linux/err.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | #include <linux/string.h> |
| 36 | #include <linux/idr.h> |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 37 | #include <linux/spinlock.h> |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 38 | #include <linux/percpu.h> |
| 39 | #include <linux/hardirq.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 40 | |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 41 | #define MAX_IDR_SHIFT (sizeof(int) * 8 - 1) |
| 42 | #define MAX_IDR_BIT (1U << MAX_IDR_SHIFT) |
| 43 | |
| 44 | /* Leave the possibility of an incomplete final layer */ |
| 45 | #define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS) |
| 46 | |
| 47 | /* Number of id_layer structs to leave in free list */ |
| 48 | #define MAX_IDR_FREE (MAX_IDR_LEVEL * 2) |
| 49 | |
Christoph Lameter | e18b890 | 2006-12-06 20:33:20 -0800 | [diff] [blame] | 50 | static struct kmem_cache *idr_layer_cache; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 51 | static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head); |
| 52 | static DEFINE_PER_CPU(int, idr_preload_cnt); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 53 | static DEFINE_SPINLOCK(simple_ida_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 55 | /* the maximum ID which can be allocated given idr->layers */ |
| 56 | static int idr_max(int layers) |
| 57 | { |
| 58 | int bits = min_t(int, layers * IDR_BITS, MAX_IDR_SHIFT); |
| 59 | |
| 60 | return (1 << bits) - 1; |
| 61 | } |
| 62 | |
Tejun Heo | 5461628 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 63 | /* |
| 64 | * Prefix mask for an idr_layer at @layer. For layer 0, the prefix mask is |
| 65 | * all bits except for the lower IDR_BITS. For layer 1, 2 * IDR_BITS, and |
| 66 | * so on. |
| 67 | */ |
| 68 | static int idr_layer_prefix_mask(int layer) |
| 69 | { |
| 70 | return ~idr_max(layer + 1); |
| 71 | } |
| 72 | |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 73 | static struct idr_layer *get_from_free_list(struct idr *idp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | { |
| 75 | struct idr_layer *p; |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 76 | unsigned long flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 78 | spin_lock_irqsave(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | if ((p = idp->id_free)) { |
| 80 | idp->id_free = p->ary[0]; |
| 81 | idp->id_free_cnt--; |
| 82 | p->ary[0] = NULL; |
| 83 | } |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 84 | spin_unlock_irqrestore(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | return(p); |
| 86 | } |
| 87 | |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 88 | /** |
| 89 | * idr_layer_alloc - allocate a new idr_layer |
| 90 | * @gfp_mask: allocation mask |
| 91 | * @layer_idr: optional idr to allocate from |
| 92 | * |
| 93 | * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch |
| 94 | * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch |
| 95 | * an idr_layer from @idr->id_free. |
| 96 | * |
| 97 | * @layer_idr is to maintain backward compatibility with the old alloc |
| 98 | * interface - idr_pre_get() and idr_get_new*() - and will be removed |
| 99 | * together with per-pool preload buffer. |
| 100 | */ |
| 101 | static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr) |
| 102 | { |
| 103 | struct idr_layer *new; |
| 104 | |
| 105 | /* this is the old path, bypass to get_from_free_list() */ |
| 106 | if (layer_idr) |
| 107 | return get_from_free_list(layer_idr); |
| 108 | |
| 109 | /* try to allocate directly from kmem_cache */ |
| 110 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
| 111 | if (new) |
| 112 | return new; |
| 113 | |
| 114 | /* |
| 115 | * Try to fetch one from the per-cpu preload buffer if in process |
| 116 | * context. See idr_preload() for details. |
| 117 | */ |
| 118 | if (in_interrupt()) |
| 119 | return NULL; |
| 120 | |
| 121 | preempt_disable(); |
| 122 | new = __this_cpu_read(idr_preload_head); |
| 123 | if (new) { |
| 124 | __this_cpu_write(idr_preload_head, new->ary[0]); |
| 125 | __this_cpu_dec(idr_preload_cnt); |
| 126 | new->ary[0] = NULL; |
| 127 | } |
| 128 | preempt_enable(); |
| 129 | return new; |
| 130 | } |
| 131 | |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 132 | static void idr_layer_rcu_free(struct rcu_head *head) |
| 133 | { |
| 134 | struct idr_layer *layer; |
| 135 | |
| 136 | layer = container_of(head, struct idr_layer, rcu_head); |
| 137 | kmem_cache_free(idr_layer_cache, layer); |
| 138 | } |
| 139 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 140 | static inline void free_layer(struct idr *idr, struct idr_layer *p) |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 141 | { |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 142 | if (idr->hint && idr->hint == p) |
| 143 | RCU_INIT_POINTER(idr->hint, NULL); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 144 | call_rcu(&p->rcu_head, idr_layer_rcu_free); |
| 145 | } |
| 146 | |
Sonny Rao | 1eec005 | 2006-06-25 05:49:34 -0700 | [diff] [blame] | 147 | /* only called when idp->lock is held */ |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 148 | static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
Sonny Rao | 1eec005 | 2006-06-25 05:49:34 -0700 | [diff] [blame] | 149 | { |
| 150 | p->ary[0] = idp->id_free; |
| 151 | idp->id_free = p; |
| 152 | idp->id_free_cnt++; |
| 153 | } |
| 154 | |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 155 | static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | { |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 157 | unsigned long flags; |
| 158 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | /* |
| 160 | * Depends on the return element being zeroed. |
| 161 | */ |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 162 | spin_lock_irqsave(&idp->lock, flags); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 163 | __move_to_free_list(idp, p); |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 164 | spin_unlock_irqrestore(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | } |
| 166 | |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 167 | static void idr_mark_full(struct idr_layer **pa, int id) |
| 168 | { |
| 169 | struct idr_layer *p = pa[0]; |
| 170 | int l = 0; |
| 171 | |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 172 | __set_bit(id & IDR_MASK, p->bitmap); |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 173 | /* |
| 174 | * If this layer is full mark the bit in the layer above to |
| 175 | * show that this part of the radix tree is full. This may |
| 176 | * complete the layer above and require walking up the radix |
| 177 | * tree. |
| 178 | */ |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 179 | while (bitmap_full(p->bitmap, IDR_SIZE)) { |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 180 | if (!(p = pa[++l])) |
| 181 | break; |
| 182 | id = id >> IDR_BITS; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 183 | __set_bit((id & IDR_MASK), p->bitmap); |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 184 | } |
| 185 | } |
| 186 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | /** |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 188 | * idr_pre_get - reserve resources for idr allocation |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | * @idp: idr handle |
| 190 | * @gfp_mask: memory allocation flags |
| 191 | * |
Naohiro Aota | 066a9be | 2010-10-26 14:23:03 -0700 | [diff] [blame] | 192 | * This function should be called prior to calling the idr_get_new* functions. |
| 193 | * It preallocates enough memory to satisfy the worst possible allocation. The |
| 194 | * caller should pass in GFP_KERNEL if possible. This of course requires that |
| 195 | * no spinning locks be held. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 197 | * If the system is REALLY out of memory this function returns %0, |
| 198 | * otherwise %1. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | */ |
Al Viro | fd4f2df | 2005-10-21 03:18:50 -0400 | [diff] [blame] | 200 | int idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | { |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 202 | while (idp->id_free_cnt < MAX_IDR_FREE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | struct idr_layer *new; |
Andrew Morton | 5b019e9 | 2009-01-15 13:51:21 -0800 | [diff] [blame] | 204 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 205 | if (new == NULL) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | return (0); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 207 | move_to_free_list(idp, new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 208 | } |
| 209 | return 1; |
| 210 | } |
| 211 | EXPORT_SYMBOL(idr_pre_get); |
| 212 | |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 213 | /** |
| 214 | * sub_alloc - try to allocate an id without growing the tree depth |
| 215 | * @idp: idr handle |
| 216 | * @starting_id: id to start search at |
| 217 | * @id: pointer to the allocated handle |
| 218 | * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 219 | * @gfp_mask: allocation mask for idr_layer_alloc() |
| 220 | * @layer_idr: optional idr passed to idr_layer_alloc() |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 221 | * |
| 222 | * Allocate an id in range [@starting_id, INT_MAX] from @idp without |
| 223 | * growing its depth. Returns |
| 224 | * |
| 225 | * the allocated id >= 0 if successful, |
| 226 | * -EAGAIN if the tree needs to grow for allocation to succeed, |
| 227 | * -ENOSPC if the id space is exhausted, |
| 228 | * -ENOMEM if more idr_layers need to be allocated. |
| 229 | */ |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 230 | static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa, |
| 231 | gfp_t gfp_mask, struct idr *layer_idr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | { |
| 233 | int n, m, sh; |
| 234 | struct idr_layer *p, *new; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 235 | int l, id, oid; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | |
| 237 | id = *starting_id; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 238 | restart: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 239 | p = idp->top; |
| 240 | l = idp->layers; |
| 241 | pa[l--] = NULL; |
| 242 | while (1) { |
| 243 | /* |
| 244 | * We run around this while until we reach the leaf node... |
| 245 | */ |
| 246 | n = (id >> (IDR_BITS*l)) & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 247 | m = find_next_zero_bit(p->bitmap, IDR_SIZE, n); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 248 | if (m == IDR_SIZE) { |
| 249 | /* no space available go back to previous layer. */ |
| 250 | l++; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 251 | oid = id; |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 252 | id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 253 | |
| 254 | /* if already at the top layer, we need to grow */ |
Tejun Heo | d2e7276 | 2010-02-22 12:44:19 -0800 | [diff] [blame] | 255 | if (id >= 1 << (idp->layers * IDR_BITS)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | *starting_id = id; |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 257 | return -EAGAIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | } |
Tejun Heo | d2e7276 | 2010-02-22 12:44:19 -0800 | [diff] [blame] | 259 | p = pa[l]; |
| 260 | BUG_ON(!p); |
Tejun Heo | 7aae6dd | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 261 | |
| 262 | /* If we need to go up one layer, continue the |
| 263 | * loop; otherwise, restart from the top. |
| 264 | */ |
| 265 | sh = IDR_BITS * (l + 1); |
| 266 | if (oid >> sh == id >> sh) |
| 267 | continue; |
| 268 | else |
| 269 | goto restart; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | } |
| 271 | if (m != n) { |
| 272 | sh = IDR_BITS*l; |
| 273 | id = ((id >> sh) ^ n ^ m) << sh; |
| 274 | } |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 275 | if ((id >= MAX_IDR_BIT) || (id < 0)) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 276 | return -ENOSPC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 277 | if (l == 0) |
| 278 | break; |
| 279 | /* |
| 280 | * Create the layer below if it is missing. |
| 281 | */ |
| 282 | if (!p->ary[m]) { |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 283 | new = idr_layer_alloc(gfp_mask, layer_idr); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 284 | if (!new) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 285 | return -ENOMEM; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 286 | new->layer = l-1; |
Tejun Heo | 5461628 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 287 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 288 | rcu_assign_pointer(p->ary[m], new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 289 | p->count++; |
| 290 | } |
| 291 | pa[l--] = p; |
| 292 | p = p->ary[m]; |
| 293 | } |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 294 | |
| 295 | pa[l] = p; |
| 296 | return id; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | } |
| 298 | |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 299 | static int idr_get_empty_slot(struct idr *idp, int starting_id, |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 300 | struct idr_layer **pa, gfp_t gfp_mask, |
| 301 | struct idr *layer_idr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | { |
| 303 | struct idr_layer *p, *new; |
| 304 | int layers, v, id; |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 305 | unsigned long flags; |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 306 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 307 | id = starting_id; |
| 308 | build_up: |
| 309 | p = idp->top; |
| 310 | layers = idp->layers; |
| 311 | if (unlikely(!p)) { |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 312 | if (!(p = idr_layer_alloc(gfp_mask, layer_idr))) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 313 | return -ENOMEM; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 314 | p->layer = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | layers = 1; |
| 316 | } |
| 317 | /* |
| 318 | * Add a new layer to the top of the tree if the requested |
| 319 | * id is larger than the currently allocated space. |
| 320 | */ |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 321 | while (id > idr_max(layers)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 322 | layers++; |
Manfred Spraul | 711a49a | 2008-12-10 18:17:06 +0100 | [diff] [blame] | 323 | if (!p->count) { |
| 324 | /* special case: if the tree is currently empty, |
| 325 | * then we grow the tree by moving the top node |
| 326 | * upwards. |
| 327 | */ |
| 328 | p->layer++; |
Tejun Heo | 5461628 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 329 | WARN_ON_ONCE(p->prefix); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 330 | continue; |
Manfred Spraul | 711a49a | 2008-12-10 18:17:06 +0100 | [diff] [blame] | 331 | } |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 332 | if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | /* |
| 334 | * The allocation failed. If we built part of |
| 335 | * the structure tear it down. |
| 336 | */ |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 337 | spin_lock_irqsave(&idp->lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | for (new = p; p && p != idp->top; new = p) { |
| 339 | p = p->ary[0]; |
| 340 | new->ary[0] = NULL; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 341 | new->count = 0; |
| 342 | bitmap_clear(new->bitmap, 0, IDR_SIZE); |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 343 | __move_to_free_list(idp, new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 344 | } |
Roland Dreier | c259cc2 | 2006-07-14 00:24:23 -0700 | [diff] [blame] | 345 | spin_unlock_irqrestore(&idp->lock, flags); |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 346 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 347 | } |
| 348 | new->ary[0] = p; |
| 349 | new->count = 1; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 350 | new->layer = layers-1; |
Tejun Heo | 5461628 | 2013-02-27 17:05:07 -0800 | [diff] [blame] | 351 | new->prefix = id & idr_layer_prefix_mask(new->layer); |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 352 | if (bitmap_full(p->bitmap, IDR_SIZE)) |
| 353 | __set_bit(0, new->bitmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 354 | p = new; |
| 355 | } |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 356 | rcu_assign_pointer(idp->top, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | idp->layers = layers; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 358 | v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr); |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 359 | if (v == -EAGAIN) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 360 | goto build_up; |
| 361 | return(v); |
| 362 | } |
| 363 | |
Tejun Heo | 3594eb2 | 2013-02-27 17:03:54 -0800 | [diff] [blame] | 364 | /* |
| 365 | * @id and @pa are from a successful allocation from idr_get_empty_slot(). |
| 366 | * Install the user pointer @ptr and mark the slot full. |
| 367 | */ |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 368 | static void idr_fill_slot(struct idr *idr, void *ptr, int id, |
| 369 | struct idr_layer **pa) |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 370 | { |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 371 | /* update hint used for lookup, cleared from free_layer() */ |
| 372 | rcu_assign_pointer(idr->hint, pa[0]); |
| 373 | |
Tejun Heo | 3594eb2 | 2013-02-27 17:03:54 -0800 | [diff] [blame] | 374 | rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
| 375 | pa[0]->count++; |
| 376 | idr_mark_full(pa, id); |
Tejun Heo | e33ac8b | 2007-06-14 03:45:12 +0900 | [diff] [blame] | 377 | } |
| 378 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 379 | /** |
John McCutchan | 7c657f2 | 2005-08-26 14:02:04 -0400 | [diff] [blame] | 380 | * idr_get_new_above - allocate new idr entry above or equal to a start id |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | * @idp: idr handle |
Thadeu Lima de Souza Cascardo | 94e2bd6 | 2009-10-16 15:20:49 +0200 | [diff] [blame] | 382 | * @ptr: pointer you want associated with the id |
Naohiro Aota | ea24ea8 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 383 | * @starting_id: id to start search at |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | * @id: pointer to the allocated handle |
| 385 | * |
| 386 | * This is the allocate id function. It should be called with any |
| 387 | * required locks. |
| 388 | * |
Naohiro Aota | 066a9be | 2010-10-26 14:23:03 -0700 | [diff] [blame] | 389 | * If allocation from IDR's private freelist fails, idr_get_new_above() will |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 390 | * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill |
Naohiro Aota | 066a9be | 2010-10-26 14:23:03 -0700 | [diff] [blame] | 391 | * IDR's preallocation and then retry the idr_get_new_above() call. |
| 392 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 393 | * If the idr is full idr_get_new_above() will return %-ENOSPC. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 395 | * @id returns a value in the range @starting_id ... %0x7fffffff |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | */ |
| 397 | int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) |
| 398 | { |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 399 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | int rv; |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 401 | |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 402 | rv = idr_get_empty_slot(idp, starting_id, pa, 0, idp); |
Nadia Derbey | 944ca05 | 2008-07-25 01:47:59 -0700 | [diff] [blame] | 403 | if (rv < 0) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 404 | return rv == -ENOMEM ? -EAGAIN : rv; |
Tejun Heo | 3594eb2 | 2013-02-27 17:03:54 -0800 | [diff] [blame] | 405 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 406 | idr_fill_slot(idp, ptr, rv, pa); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | *id = rv; |
| 408 | return 0; |
| 409 | } |
| 410 | EXPORT_SYMBOL(idr_get_new_above); |
| 411 | |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 412 | /** |
| 413 | * idr_preload - preload for idr_alloc() |
| 414 | * @gfp_mask: allocation mask to use for preloading |
| 415 | * |
| 416 | * Preload per-cpu layer buffer for idr_alloc(). Can only be used from |
| 417 | * process context and each idr_preload() invocation should be matched with |
| 418 | * idr_preload_end(). Note that preemption is disabled while preloaded. |
| 419 | * |
| 420 | * The first idr_alloc() in the preloaded section can be treated as if it |
| 421 | * were invoked with @gfp_mask used for preloading. This allows using more |
| 422 | * permissive allocation masks for idrs protected by spinlocks. |
| 423 | * |
| 424 | * For example, if idr_alloc() below fails, the failure can be treated as |
| 425 | * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT. |
| 426 | * |
| 427 | * idr_preload(GFP_KERNEL); |
| 428 | * spin_lock(lock); |
| 429 | * |
| 430 | * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT); |
| 431 | * |
| 432 | * spin_unlock(lock); |
| 433 | * idr_preload_end(); |
| 434 | * if (id < 0) |
| 435 | * error; |
| 436 | */ |
| 437 | void idr_preload(gfp_t gfp_mask) |
| 438 | { |
| 439 | /* |
| 440 | * Consuming preload buffer from non-process context breaks preload |
| 441 | * allocation guarantee. Disallow usage from those contexts. |
| 442 | */ |
| 443 | WARN_ON_ONCE(in_interrupt()); |
| 444 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 445 | |
| 446 | preempt_disable(); |
| 447 | |
| 448 | /* |
| 449 | * idr_alloc() is likely to succeed w/o full idr_layer buffer and |
| 450 | * return value from idr_alloc() needs to be checked for failure |
| 451 | * anyway. Silently give up if allocation fails. The caller can |
| 452 | * treat failures from idr_alloc() as if idr_alloc() were called |
| 453 | * with @gfp_mask which should be enough. |
| 454 | */ |
| 455 | while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) { |
| 456 | struct idr_layer *new; |
| 457 | |
| 458 | preempt_enable(); |
| 459 | new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
| 460 | preempt_disable(); |
| 461 | if (!new) |
| 462 | break; |
| 463 | |
| 464 | /* link the new one to per-cpu preload list */ |
| 465 | new->ary[0] = __this_cpu_read(idr_preload_head); |
| 466 | __this_cpu_write(idr_preload_head, new); |
| 467 | __this_cpu_inc(idr_preload_cnt); |
| 468 | } |
| 469 | } |
| 470 | EXPORT_SYMBOL(idr_preload); |
| 471 | |
| 472 | /** |
| 473 | * idr_alloc - allocate new idr entry |
| 474 | * @idr: the (initialized) idr |
| 475 | * @ptr: pointer to be associated with the new id |
| 476 | * @start: the minimum id (inclusive) |
| 477 | * @end: the maximum id (exclusive, <= 0 for max) |
| 478 | * @gfp_mask: memory allocation flags |
| 479 | * |
| 480 | * Allocate an id in [start, end) and associate it with @ptr. If no ID is |
| 481 | * available in the specified range, returns -ENOSPC. On memory allocation |
| 482 | * failure, returns -ENOMEM. |
| 483 | * |
| 484 | * Note that @end is treated as max when <= 0. This is to always allow |
| 485 | * using @start + N as @end as long as N is inside integer range. |
| 486 | * |
| 487 | * The user is responsible for exclusively synchronizing all operations |
| 488 | * which may modify @idr. However, read-only accesses such as idr_find() |
| 489 | * or iteration can be performed under RCU read lock provided the user |
| 490 | * destroys @ptr in RCU-safe way after removal from idr. |
| 491 | */ |
| 492 | int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask) |
| 493 | { |
| 494 | int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */ |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 495 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 496 | int id; |
| 497 | |
| 498 | might_sleep_if(gfp_mask & __GFP_WAIT); |
| 499 | |
| 500 | /* sanity checks */ |
| 501 | if (WARN_ON_ONCE(start < 0)) |
| 502 | return -EINVAL; |
| 503 | if (unlikely(max < start)) |
| 504 | return -ENOSPC; |
| 505 | |
| 506 | /* allocate id */ |
| 507 | id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL); |
| 508 | if (unlikely(id < 0)) |
| 509 | return id; |
| 510 | if (unlikely(id > max)) |
| 511 | return -ENOSPC; |
| 512 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 513 | idr_fill_slot(idr, ptr, id, pa); |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 514 | return id; |
| 515 | } |
| 516 | EXPORT_SYMBOL_GPL(idr_alloc); |
| 517 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 518 | static void idr_remove_warning(int id) |
| 519 | { |
Nadia Derbey | f098ad6 | 2008-07-25 01:47:59 -0700 | [diff] [blame] | 520 | printk(KERN_WARNING |
| 521 | "idr_remove called for id=%d which is not allocated.\n", id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | dump_stack(); |
| 523 | } |
| 524 | |
| 525 | static void sub_remove(struct idr *idp, int shift, int id) |
| 526 | { |
| 527 | struct idr_layer *p = idp->top; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 528 | struct idr_layer **pa[MAX_IDR_LEVEL + 1]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | struct idr_layer ***paa = &pa[0]; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 530 | struct idr_layer *to_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 531 | int n; |
| 532 | |
| 533 | *paa = NULL; |
| 534 | *++paa = &idp->top; |
| 535 | |
| 536 | while ((shift > 0) && p) { |
| 537 | n = (id >> shift) & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 538 | __clear_bit(n, p->bitmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 539 | *++paa = &p->ary[n]; |
| 540 | p = p->ary[n]; |
| 541 | shift -= IDR_BITS; |
| 542 | } |
| 543 | n = id & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 544 | if (likely(p != NULL && test_bit(n, p->bitmap))) { |
| 545 | __clear_bit(n, p->bitmap); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 546 | rcu_assign_pointer(p->ary[n], NULL); |
| 547 | to_free = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 548 | while(*paa && ! --((**paa)->count)){ |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 549 | if (to_free) |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 550 | free_layer(idp, to_free); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 551 | to_free = **paa; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | **paa-- = NULL; |
| 553 | } |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 554 | if (!*paa) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 555 | idp->layers = 0; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 556 | if (to_free) |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 557 | free_layer(idp, to_free); |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 558 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 559 | idr_remove_warning(id); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 560 | } |
| 561 | |
| 562 | /** |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 563 | * idr_remove - remove the given id and free its slot |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 564 | * @idp: idr handle |
| 565 | * @id: unique key |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 566 | */ |
| 567 | void idr_remove(struct idr *idp, int id) |
| 568 | { |
| 569 | struct idr_layer *p; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 570 | struct idr_layer *to_free; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 571 | |
Tejun Heo | 2e1c9b2 | 2013-03-08 12:43:30 -0800 | [diff] [blame] | 572 | if (id < 0) |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 573 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 574 | |
| 575 | sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); |
Jesper Juhl | e15ae2d | 2005-10-30 15:02:14 -0800 | [diff] [blame] | 576 | if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 577 | idp->top->ary[0]) { |
| 578 | /* |
| 579 | * Single child at leftmost slot: we can shrink the tree. |
| 580 | * This level is not needed anymore since when layers are |
| 581 | * inserted, they are inserted at the top of the existing |
| 582 | * tree. |
| 583 | */ |
| 584 | to_free = idp->top; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 585 | p = idp->top->ary[0]; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 586 | rcu_assign_pointer(idp->top, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 587 | --idp->layers; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 588 | to_free->count = 0; |
| 589 | bitmap_clear(to_free->bitmap, 0, IDR_SIZE); |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 590 | free_layer(idp, to_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 591 | } |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 592 | while (idp->id_free_cnt >= MAX_IDR_FREE) { |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 593 | p = get_from_free_list(idp); |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 594 | /* |
| 595 | * Note: we don't call the rcu callback here, since the only |
| 596 | * layers that fall into the freelist are those that have been |
| 597 | * preallocated. |
| 598 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 599 | kmem_cache_free(idr_layer_cache, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | } |
Nadia Derbey | af8e2a4 | 2008-05-01 04:34:57 -0700 | [diff] [blame] | 601 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 602 | } |
| 603 | EXPORT_SYMBOL(idr_remove); |
| 604 | |
Tejun Heo | fe6e24e | 2013-02-27 17:03:50 -0800 | [diff] [blame] | 605 | void __idr_remove_all(struct idr *idp) |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 606 | { |
Oleg Nesterov | 6ace06dc | 2007-07-31 00:39:19 -0700 | [diff] [blame] | 607 | int n, id, max; |
Imre Deak | 2dcb22b | 2010-05-26 14:43:38 -0700 | [diff] [blame] | 608 | int bt_mask; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 609 | struct idr_layer *p; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 610 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 611 | struct idr_layer **paa = &pa[0]; |
| 612 | |
| 613 | n = idp->layers * IDR_BITS; |
| 614 | p = idp->top; |
Paul E. McKenney | 1b23336 | 2009-03-10 12:55:52 -0700 | [diff] [blame] | 615 | rcu_assign_pointer(idp->top, NULL); |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 616 | max = idr_max(idp->layers); |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 617 | |
| 618 | id = 0; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 619 | while (id >= 0 && id <= max) { |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 620 | while (n > IDR_BITS && p) { |
| 621 | n -= IDR_BITS; |
| 622 | *paa++ = p; |
| 623 | p = p->ary[(id >> n) & IDR_MASK]; |
| 624 | } |
| 625 | |
Imre Deak | 2dcb22b | 2010-05-26 14:43:38 -0700 | [diff] [blame] | 626 | bt_mask = id; |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 627 | id += 1 << n; |
Imre Deak | 2dcb22b | 2010-05-26 14:43:38 -0700 | [diff] [blame] | 628 | /* Get the highest bit that the above add changed from 0->1. */ |
| 629 | while (n < fls(id ^ bt_mask)) { |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 630 | if (p) |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 631 | free_layer(idp, p); |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 632 | n += IDR_BITS; |
| 633 | p = *--paa; |
| 634 | } |
| 635 | } |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 636 | idp->layers = 0; |
| 637 | } |
Tejun Heo | fe6e24e | 2013-02-27 17:03:50 -0800 | [diff] [blame] | 638 | EXPORT_SYMBOL(__idr_remove_all); |
Kristian Hoegsberg | 23936cc | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 639 | |
| 640 | /** |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 641 | * idr_destroy - release all cached layers within an idr tree |
Naohiro Aota | ea24ea8 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 642 | * @idp: idr handle |
Tejun Heo | 9bb26bc | 2013-02-27 17:03:35 -0800 | [diff] [blame] | 643 | * |
| 644 | * Free all id mappings and all idp_layers. After this function, @idp is |
| 645 | * completely unused and can be freed / recycled. The caller is |
| 646 | * responsible for ensuring that no one else accesses @idp during or after |
| 647 | * idr_destroy(). |
| 648 | * |
| 649 | * A typical clean-up sequence for objects stored in an idr tree will use |
| 650 | * idr_for_each() to free all objects, if necessay, then idr_destroy() to |
| 651 | * free up the id mappings and cached idr_layers. |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 652 | */ |
| 653 | void idr_destroy(struct idr *idp) |
| 654 | { |
Tejun Heo | fe6e24e | 2013-02-27 17:03:50 -0800 | [diff] [blame] | 655 | __idr_remove_all(idp); |
Tejun Heo | 9bb26bc | 2013-02-27 17:03:35 -0800 | [diff] [blame] | 656 | |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 657 | while (idp->id_free_cnt) { |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 658 | struct idr_layer *p = get_from_free_list(idp); |
Andrew Morton | 8d3b359 | 2005-10-23 12:57:18 -0700 | [diff] [blame] | 659 | kmem_cache_free(idr_layer_cache, p); |
| 660 | } |
| 661 | } |
| 662 | EXPORT_SYMBOL(idr_destroy); |
| 663 | |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 664 | void *idr_find_slowpath(struct idr *idp, int id) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 665 | { |
| 666 | int n; |
| 667 | struct idr_layer *p; |
| 668 | |
Tejun Heo | 2e1c9b2 | 2013-03-08 12:43:30 -0800 | [diff] [blame] | 669 | if (id < 0) |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 670 | return NULL; |
| 671 | |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 672 | p = rcu_dereference_raw(idp->top); |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 673 | if (!p) |
| 674 | return NULL; |
| 675 | n = (p->layer+1) * IDR_BITS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 676 | |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 677 | if (id > idr_max(p->layer + 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 678 | return NULL; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 679 | BUG_ON(n == 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 680 | |
| 681 | while (n > 0 && p) { |
| 682 | n -= IDR_BITS; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 683 | BUG_ON(n != p->layer*IDR_BITS); |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 684 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 685 | } |
| 686 | return((void *)p); |
| 687 | } |
Tejun Heo | 0ffc2a9 | 2013-02-27 17:05:08 -0800 | [diff] [blame] | 688 | EXPORT_SYMBOL(idr_find_slowpath); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 689 | |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 690 | /** |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 691 | * idr_for_each - iterate through all stored pointers |
| 692 | * @idp: idr handle |
| 693 | * @fn: function to be called for each pointer |
| 694 | * @data: data passed back to callback function |
| 695 | * |
| 696 | * Iterate over the pointers registered with the given idr. The |
| 697 | * callback function will be called for each pointer currently |
| 698 | * registered, passing the id, the pointer and the data pointer passed |
| 699 | * to this function. It is not safe to modify the idr tree while in |
| 700 | * the callback, so functions such as idr_get_new and idr_remove are |
| 701 | * not allowed. |
| 702 | * |
| 703 | * We check the return of @fn each time. If it returns anything other |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 704 | * than %0, we break out and return that value. |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 705 | * |
| 706 | * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). |
| 707 | */ |
| 708 | int idr_for_each(struct idr *idp, |
| 709 | int (*fn)(int id, void *p, void *data), void *data) |
| 710 | { |
| 711 | int n, id, max, error = 0; |
| 712 | struct idr_layer *p; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 713 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 714 | struct idr_layer **paa = &pa[0]; |
| 715 | |
| 716 | n = idp->layers * IDR_BITS; |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 717 | p = rcu_dereference_raw(idp->top); |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 718 | max = idr_max(idp->layers); |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 719 | |
| 720 | id = 0; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 721 | while (id >= 0 && id <= max) { |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 722 | while (n > 0 && p) { |
| 723 | n -= IDR_BITS; |
| 724 | *paa++ = p; |
Paul E. McKenney | 96be753 | 2010-02-22 17:04:55 -0800 | [diff] [blame] | 725 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
Kristian Hoegsberg | 96d7fa4 | 2007-07-15 23:37:24 -0700 | [diff] [blame] | 726 | } |
| 727 | |
| 728 | if (p) { |
| 729 | error = fn(id, (void *)p, data); |
| 730 | if (error) |
| 731 | break; |
| 732 | } |
| 733 | |
| 734 | id += 1 << n; |
| 735 | while (n < fls(id)) { |
| 736 | n += IDR_BITS; |
| 737 | p = *--paa; |
| 738 | } |
| 739 | } |
| 740 | |
| 741 | return error; |
| 742 | } |
| 743 | EXPORT_SYMBOL(idr_for_each); |
| 744 | |
| 745 | /** |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 746 | * idr_get_next - lookup next object of id to given id. |
| 747 | * @idp: idr handle |
Naohiro Aota | ea24ea8 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 748 | * @nextidp: pointer to lookup key |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 749 | * |
| 750 | * Returns pointer to registered object with id, which is next number to |
Naohiro Aota | 1458ce1 | 2010-08-27 17:43:46 +0900 | [diff] [blame] | 751 | * given id. After being looked up, *@nextidp will be updated for the next |
| 752 | * iteration. |
Hugh Dickins | 9f7de82 | 2012-03-21 16:34:20 -0700 | [diff] [blame] | 753 | * |
| 754 | * This function can be called under rcu_read_lock(), given that the leaf |
| 755 | * pointers lifetimes are correctly managed. |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 756 | */ |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 757 | void *idr_get_next(struct idr *idp, int *nextidp) |
| 758 | { |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 759 | struct idr_layer *p, *pa[MAX_IDR_LEVEL + 1]; |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 760 | struct idr_layer **paa = &pa[0]; |
| 761 | int id = *nextidp; |
| 762 | int n, max; |
| 763 | |
| 764 | /* find first ent */ |
Paul E. McKenney | 94bfa3b | 2010-06-07 17:09:45 -0700 | [diff] [blame] | 765 | p = rcu_dereference_raw(idp->top); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 766 | if (!p) |
| 767 | return NULL; |
Hugh Dickins | 9f7de82 | 2012-03-21 16:34:20 -0700 | [diff] [blame] | 768 | n = (p->layer + 1) * IDR_BITS; |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 769 | max = idr_max(p->layer + 1); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 770 | |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 771 | while (id >= 0 && id <= max) { |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 772 | while (n > 0 && p) { |
| 773 | n -= IDR_BITS; |
| 774 | *paa++ = p; |
Paul E. McKenney | 94bfa3b | 2010-06-07 17:09:45 -0700 | [diff] [blame] | 775 | p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 776 | } |
| 777 | |
| 778 | if (p) { |
| 779 | *nextidp = id; |
| 780 | return p; |
| 781 | } |
| 782 | |
Tejun Heo | 6cdae74 | 2013-02-27 17:03:34 -0800 | [diff] [blame] | 783 | /* |
| 784 | * Proceed to the next layer at the current level. Unlike |
| 785 | * idr_for_each(), @id isn't guaranteed to be aligned to |
| 786 | * layer boundary at this point and adding 1 << n may |
| 787 | * incorrectly skip IDs. Make sure we jump to the |
| 788 | * beginning of the next layer using round_up(). |
| 789 | */ |
| 790 | id = round_up(id + 1, 1 << n); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 791 | while (n < fls(id)) { |
| 792 | n += IDR_BITS; |
| 793 | p = *--paa; |
| 794 | } |
| 795 | } |
| 796 | return NULL; |
| 797 | } |
Ben Hutchings | 4d1ee80 | 2010-01-29 20:59:17 +0000 | [diff] [blame] | 798 | EXPORT_SYMBOL(idr_get_next); |
KAMEZAWA Hiroyuki | 38460b4 | 2009-04-02 16:57:25 -0700 | [diff] [blame] | 799 | |
| 800 | |
| 801 | /** |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 802 | * idr_replace - replace pointer for given id |
| 803 | * @idp: idr handle |
| 804 | * @ptr: pointer you want associated with the id |
| 805 | * @id: lookup key |
| 806 | * |
| 807 | * Replace the pointer registered with an id and return the old value. |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 808 | * A %-ENOENT return indicates that @id was not found. |
| 809 | * A %-EINVAL return indicates that @id was not within valid constraints. |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 810 | * |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 811 | * The caller must serialize with writers. |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 812 | */ |
| 813 | void *idr_replace(struct idr *idp, void *ptr, int id) |
| 814 | { |
| 815 | int n; |
| 816 | struct idr_layer *p, *old_p; |
| 817 | |
Tejun Heo | 2e1c9b2 | 2013-03-08 12:43:30 -0800 | [diff] [blame] | 818 | if (id < 0) |
Tejun Heo | e8c8d1b | 2013-02-27 17:05:04 -0800 | [diff] [blame] | 819 | return ERR_PTR(-EINVAL); |
| 820 | |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 821 | p = idp->top; |
Manfred Spraul | 6ff2d39 | 2008-12-01 13:14:02 -0800 | [diff] [blame] | 822 | if (!p) |
| 823 | return ERR_PTR(-EINVAL); |
| 824 | |
| 825 | n = (p->layer+1) * IDR_BITS; |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 826 | |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 827 | if (id >= (1 << n)) |
| 828 | return ERR_PTR(-EINVAL); |
| 829 | |
| 830 | n -= IDR_BITS; |
| 831 | while ((n > 0) && p) { |
| 832 | p = p->ary[(id >> n) & IDR_MASK]; |
| 833 | n -= IDR_BITS; |
| 834 | } |
| 835 | |
| 836 | n = id & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 837 | if (unlikely(p == NULL || !test_bit(n, p->bitmap))) |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 838 | return ERR_PTR(-ENOENT); |
| 839 | |
| 840 | old_p = p->ary[n]; |
Nadia Derbey | cf481c2 | 2008-07-25 01:48:02 -0700 | [diff] [blame] | 841 | rcu_assign_pointer(p->ary[n], ptr); |
Jeff Mahoney | 5806f07 | 2006-06-26 00:27:19 -0700 | [diff] [blame] | 842 | |
| 843 | return old_p; |
| 844 | } |
| 845 | EXPORT_SYMBOL(idr_replace); |
| 846 | |
Akinobu Mita | 199f0ca | 2008-04-29 01:03:13 -0700 | [diff] [blame] | 847 | void __init idr_init_cache(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 848 | { |
Akinobu Mita | 199f0ca | 2008-04-29 01:03:13 -0700 | [diff] [blame] | 849 | idr_layer_cache = kmem_cache_create("idr_layer_cache", |
Andrew Morton | 5b019e9 | 2009-01-15 13:51:21 -0800 | [diff] [blame] | 850 | sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | } |
| 852 | |
| 853 | /** |
| 854 | * idr_init - initialize idr handle |
| 855 | * @idp: idr handle |
| 856 | * |
| 857 | * This function is use to set up the handle (@idp) that you will pass |
| 858 | * to the rest of the functions. |
| 859 | */ |
| 860 | void idr_init(struct idr *idp) |
| 861 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 862 | memset(idp, 0, sizeof(struct idr)); |
| 863 | spin_lock_init(&idp->lock); |
| 864 | } |
| 865 | EXPORT_SYMBOL(idr_init); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 866 | |
| 867 | |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 868 | /** |
| 869 | * DOC: IDA description |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 870 | * IDA - IDR based ID allocator |
| 871 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 872 | * This is id allocator without id -> pointer translation. Memory |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 873 | * usage is much lower than full blown idr because each id only |
| 874 | * occupies a bit. ida uses a custom leaf node which contains |
| 875 | * IDA_BITMAP_BITS slots. |
| 876 | * |
| 877 | * 2007-04-25 written by Tejun Heo <htejun@gmail.com> |
| 878 | */ |
| 879 | |
| 880 | static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) |
| 881 | { |
| 882 | unsigned long flags; |
| 883 | |
| 884 | if (!ida->free_bitmap) { |
| 885 | spin_lock_irqsave(&ida->idr.lock, flags); |
| 886 | if (!ida->free_bitmap) { |
| 887 | ida->free_bitmap = bitmap; |
| 888 | bitmap = NULL; |
| 889 | } |
| 890 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
| 891 | } |
| 892 | |
| 893 | kfree(bitmap); |
| 894 | } |
| 895 | |
| 896 | /** |
| 897 | * ida_pre_get - reserve resources for ida allocation |
| 898 | * @ida: ida handle |
| 899 | * @gfp_mask: memory allocation flag |
| 900 | * |
| 901 | * This function should be called prior to locking and calling the |
| 902 | * following function. It preallocates enough memory to satisfy the |
| 903 | * worst possible allocation. |
| 904 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 905 | * If the system is REALLY out of memory this function returns %0, |
| 906 | * otherwise %1. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 907 | */ |
| 908 | int ida_pre_get(struct ida *ida, gfp_t gfp_mask) |
| 909 | { |
| 910 | /* allocate idr_layers */ |
| 911 | if (!idr_pre_get(&ida->idr, gfp_mask)) |
| 912 | return 0; |
| 913 | |
| 914 | /* allocate free_bitmap */ |
| 915 | if (!ida->free_bitmap) { |
| 916 | struct ida_bitmap *bitmap; |
| 917 | |
| 918 | bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); |
| 919 | if (!bitmap) |
| 920 | return 0; |
| 921 | |
| 922 | free_bitmap(ida, bitmap); |
| 923 | } |
| 924 | |
| 925 | return 1; |
| 926 | } |
| 927 | EXPORT_SYMBOL(ida_pre_get); |
| 928 | |
| 929 | /** |
| 930 | * ida_get_new_above - allocate new ID above or equal to a start id |
| 931 | * @ida: ida handle |
Naohiro Aota | ea24ea8 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 932 | * @starting_id: id to start search at |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 933 | * @p_id: pointer to the allocated handle |
| 934 | * |
Wang Sheng-Hui | e3816c5 | 2011-10-31 17:12:36 -0700 | [diff] [blame] | 935 | * Allocate new ID above or equal to @starting_id. It should be called |
| 936 | * with any required locks. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 937 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 938 | * If memory is required, it will return %-EAGAIN, you should unlock |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 939 | * and go back to the ida_pre_get() call. If the ida is full, it will |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 940 | * return %-ENOSPC. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 941 | * |
Randy Dunlap | 56083ab | 2010-10-26 14:19:08 -0700 | [diff] [blame] | 942 | * @p_id returns a value in the range @starting_id ... %0x7fffffff. |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 943 | */ |
| 944 | int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) |
| 945 | { |
Tejun Heo | 326cf0f | 2013-02-27 17:05:02 -0800 | [diff] [blame] | 946 | struct idr_layer *pa[MAX_IDR_LEVEL + 1]; |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 947 | struct ida_bitmap *bitmap; |
| 948 | unsigned long flags; |
| 949 | int idr_id = starting_id / IDA_BITMAP_BITS; |
| 950 | int offset = starting_id % IDA_BITMAP_BITS; |
| 951 | int t, id; |
| 952 | |
| 953 | restart: |
| 954 | /* get vacant slot */ |
Tejun Heo | d5c7409 | 2013-02-27 17:03:55 -0800 | [diff] [blame] | 955 | t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr); |
Nadia Derbey | 944ca05 | 2008-07-25 01:47:59 -0700 | [diff] [blame] | 956 | if (t < 0) |
Tejun Heo | 12d1b43 | 2013-02-27 17:03:53 -0800 | [diff] [blame] | 957 | return t == -ENOMEM ? -EAGAIN : t; |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 958 | |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 959 | if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 960 | return -ENOSPC; |
| 961 | |
| 962 | if (t != idr_id) |
| 963 | offset = 0; |
| 964 | idr_id = t; |
| 965 | |
| 966 | /* if bitmap isn't there, create a new one */ |
| 967 | bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; |
| 968 | if (!bitmap) { |
| 969 | spin_lock_irqsave(&ida->idr.lock, flags); |
| 970 | bitmap = ida->free_bitmap; |
| 971 | ida->free_bitmap = NULL; |
| 972 | spin_unlock_irqrestore(&ida->idr.lock, flags); |
| 973 | |
| 974 | if (!bitmap) |
| 975 | return -EAGAIN; |
| 976 | |
| 977 | memset(bitmap, 0, sizeof(struct ida_bitmap)); |
Nadia Derbey | 3219b3b | 2008-07-25 01:48:00 -0700 | [diff] [blame] | 978 | rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], |
| 979 | (void *)bitmap); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 980 | pa[0]->count++; |
| 981 | } |
| 982 | |
| 983 | /* lookup for empty slot */ |
| 984 | t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); |
| 985 | if (t == IDA_BITMAP_BITS) { |
| 986 | /* no empty slot after offset, continue to the next chunk */ |
| 987 | idr_id++; |
| 988 | offset = 0; |
| 989 | goto restart; |
| 990 | } |
| 991 | |
| 992 | id = idr_id * IDA_BITMAP_BITS + t; |
Fengguang Wu | 125c4c7 | 2012-10-04 17:13:15 -0700 | [diff] [blame] | 993 | if (id >= MAX_IDR_BIT) |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 994 | return -ENOSPC; |
| 995 | |
| 996 | __set_bit(t, bitmap->bitmap); |
| 997 | if (++bitmap->nr_busy == IDA_BITMAP_BITS) |
| 998 | idr_mark_full(pa, idr_id); |
| 999 | |
| 1000 | *p_id = id; |
| 1001 | |
| 1002 | /* Each leaf node can handle nearly a thousand slots and the |
| 1003 | * whole idea of ida is to have small memory foot print. |
| 1004 | * Throw away extra resources one by one after each successful |
| 1005 | * allocation. |
| 1006 | */ |
| 1007 | if (ida->idr.id_free_cnt || ida->free_bitmap) { |
Nadia Derbey | 4ae5378 | 2008-07-25 01:47:58 -0700 | [diff] [blame] | 1008 | struct idr_layer *p = get_from_free_list(&ida->idr); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1009 | if (p) |
| 1010 | kmem_cache_free(idr_layer_cache, p); |
| 1011 | } |
| 1012 | |
| 1013 | return 0; |
| 1014 | } |
| 1015 | EXPORT_SYMBOL(ida_get_new_above); |
| 1016 | |
| 1017 | /** |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1018 | * ida_remove - remove the given ID |
| 1019 | * @ida: ida handle |
| 1020 | * @id: ID to free |
| 1021 | */ |
| 1022 | void ida_remove(struct ida *ida, int id) |
| 1023 | { |
| 1024 | struct idr_layer *p = ida->idr.top; |
| 1025 | int shift = (ida->idr.layers - 1) * IDR_BITS; |
| 1026 | int idr_id = id / IDA_BITMAP_BITS; |
| 1027 | int offset = id % IDA_BITMAP_BITS; |
| 1028 | int n; |
| 1029 | struct ida_bitmap *bitmap; |
| 1030 | |
| 1031 | /* clear full bits while looking up the leaf idr_layer */ |
| 1032 | while ((shift > 0) && p) { |
| 1033 | n = (idr_id >> shift) & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 1034 | __clear_bit(n, p->bitmap); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1035 | p = p->ary[n]; |
| 1036 | shift -= IDR_BITS; |
| 1037 | } |
| 1038 | |
| 1039 | if (p == NULL) |
| 1040 | goto err; |
| 1041 | |
| 1042 | n = idr_id & IDR_MASK; |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 1043 | __clear_bit(n, p->bitmap); |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1044 | |
| 1045 | bitmap = (void *)p->ary[n]; |
| 1046 | if (!test_bit(offset, bitmap->bitmap)) |
| 1047 | goto err; |
| 1048 | |
| 1049 | /* update bitmap and remove it if empty */ |
| 1050 | __clear_bit(offset, bitmap->bitmap); |
| 1051 | if (--bitmap->nr_busy == 0) { |
Tejun Heo | 1d9b2e1 | 2013-02-27 17:05:05 -0800 | [diff] [blame] | 1052 | __set_bit(n, p->bitmap); /* to please idr_remove() */ |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1053 | idr_remove(&ida->idr, idr_id); |
| 1054 | free_bitmap(ida, bitmap); |
| 1055 | } |
| 1056 | |
| 1057 | return; |
| 1058 | |
| 1059 | err: |
| 1060 | printk(KERN_WARNING |
| 1061 | "ida_remove called for id=%d which is not allocated.\n", id); |
| 1062 | } |
| 1063 | EXPORT_SYMBOL(ida_remove); |
| 1064 | |
| 1065 | /** |
| 1066 | * ida_destroy - release all cached layers within an ida tree |
Naohiro Aota | ea24ea8 | 2010-08-31 00:37:03 +0900 | [diff] [blame] | 1067 | * @ida: ida handle |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1068 | */ |
| 1069 | void ida_destroy(struct ida *ida) |
| 1070 | { |
| 1071 | idr_destroy(&ida->idr); |
| 1072 | kfree(ida->free_bitmap); |
| 1073 | } |
| 1074 | EXPORT_SYMBOL(ida_destroy); |
| 1075 | |
| 1076 | /** |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1077 | * ida_simple_get - get a new id. |
| 1078 | * @ida: the (initialized) ida. |
| 1079 | * @start: the minimum id (inclusive, < 0x8000000) |
| 1080 | * @end: the maximum id (exclusive, < 0x8000000 or 0) |
| 1081 | * @gfp_mask: memory allocation flags |
| 1082 | * |
| 1083 | * Allocates an id in the range start <= id < end, or returns -ENOSPC. |
| 1084 | * On memory allocation failure, returns -ENOMEM. |
| 1085 | * |
| 1086 | * Use ida_simple_remove() to get rid of an id. |
| 1087 | */ |
| 1088 | int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, |
| 1089 | gfp_t gfp_mask) |
| 1090 | { |
| 1091 | int ret, id; |
| 1092 | unsigned int max; |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1093 | unsigned long flags; |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1094 | |
| 1095 | BUG_ON((int)start < 0); |
| 1096 | BUG_ON((int)end < 0); |
| 1097 | |
| 1098 | if (end == 0) |
| 1099 | max = 0x80000000; |
| 1100 | else { |
| 1101 | BUG_ON(end < start); |
| 1102 | max = end - 1; |
| 1103 | } |
| 1104 | |
| 1105 | again: |
| 1106 | if (!ida_pre_get(ida, gfp_mask)) |
| 1107 | return -ENOMEM; |
| 1108 | |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1109 | spin_lock_irqsave(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1110 | ret = ida_get_new_above(ida, start, &id); |
| 1111 | if (!ret) { |
| 1112 | if (id > max) { |
| 1113 | ida_remove(ida, id); |
| 1114 | ret = -ENOSPC; |
| 1115 | } else { |
| 1116 | ret = id; |
| 1117 | } |
| 1118 | } |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1119 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1120 | |
| 1121 | if (unlikely(ret == -EAGAIN)) |
| 1122 | goto again; |
| 1123 | |
| 1124 | return ret; |
| 1125 | } |
| 1126 | EXPORT_SYMBOL(ida_simple_get); |
| 1127 | |
| 1128 | /** |
| 1129 | * ida_simple_remove - remove an allocated id. |
| 1130 | * @ida: the (initialized) ida. |
| 1131 | * @id: the id returned by ida_simple_get. |
| 1132 | */ |
| 1133 | void ida_simple_remove(struct ida *ida, unsigned int id) |
| 1134 | { |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1135 | unsigned long flags; |
| 1136 | |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1137 | BUG_ON((int)id < 0); |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1138 | spin_lock_irqsave(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1139 | ida_remove(ida, id); |
Tejun Heo | 46cbc1d | 2011-11-02 13:38:46 -0700 | [diff] [blame] | 1140 | spin_unlock_irqrestore(&simple_ida_lock, flags); |
Rusty Russell | 88eca02 | 2011-08-03 16:21:06 -0700 | [diff] [blame] | 1141 | } |
| 1142 | EXPORT_SYMBOL(ida_simple_remove); |
| 1143 | |
| 1144 | /** |
Tejun Heo | 72dba58 | 2007-06-14 03:45:13 +0900 | [diff] [blame] | 1145 | * ida_init - initialize ida handle |
| 1146 | * @ida: ida handle |
| 1147 | * |
| 1148 | * This function is use to set up the handle (@ida) that you will pass |
| 1149 | * to the rest of the functions. |
| 1150 | */ |
| 1151 | void ida_init(struct ida *ida) |
| 1152 | { |
| 1153 | memset(ida, 0, sizeof(struct ida)); |
| 1154 | idr_init(&ida->idr); |
| 1155 | |
| 1156 | } |
| 1157 | EXPORT_SYMBOL(ida_init); |